Editor's Letter
Chemical Research
In this work, we review the concept of Push-Pull (donor-acceptor) as a strategy for the activation of inert molecules
or the stabilization of highly reactive fragments. This model is based on the combination of an electron-rich and an electron-poor center that, in a concerted manner, can donate (push) and withdraw (pull) electron density from
another molecular fragment. This perspective describes various examples that demonstrate the interest and applicability of this strategy, including systems that enable the activation of inert molecules such as CO2 or N2, as well as others that allow the stabilization of highly reactive fragments like LiH or LiMe.
Chemistry Teaching
Technetium (Tc) is a metallic element with atomic number 43, which occupies the group 7 and period 5 in the periodic table. It was not properly identified until 1937, when Carlo Perrier and Emilio Segre characterized it as a product of nuclear reactions in the recently invented cyclotron. Its chemistry is rich and versatile due to the large number of existing compounds and complexes, especially with oxidation state +7. Its main application is in medical imaging, such as tomography and scintigraphy. For this purpose, the isotope 99mTc is widely used. It is also employed in the manufacture of alloys and as a catalyst. Despite being considered a synthetic element, it can be found in nature but only in trace amounts.
Keywords: technetium, isotopes, nuclear isomers, radioactivity, scintigraphy